From the introduction:
Return to Axanar is designed for Star Fleet Military Operations Command personnel serving aboard the USS Cooper, a 121,300 metric-ton Baker Class destroyer. The adventure involves action on a Class M planet, as well as in space. To play this game, the gamemaster will need the second edition of STAR TREK: The Role Playing Game, as well as the STAR TREK III Starship Combat Role Playing Game. It might also prove helpful to have The Klingons supplement.